# Charging cap with three phase

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#### Andrew Borg

Aug 10, 2014
42
Sir I need to charge a capacitor with three phase generator. Did three diode bridge but not charging. Any clue pls?
Thks

#### duke37

Jan 9, 2011
5,364
Three diodes will need a four wire drive.
Six diodes in a bridge can operate without the common wire.

#### Andrew Borg

Aug 10, 2014
42
Hi duke37 you're right I meant six diodes regarding the bridge. I connected the three wires coming out of the generator to the middle of those six diodes but cap not charging.

Nov 20, 2018
51

#### duke37

Jan 9, 2011
5,364
Disconnect the bridge,
Measure the resistance between the alternator outputs. Three readings.
Measure the output voltage between the three alternator outputs when running. Three readings.

Measure the resistance or voltage drop of each diode at both polarity. Twelve readings.
If one reading is different to the rest, disconnrct one end and measure it on its own.
Measure voltage drop across the bridge at each polarity. Two readings.

#### Andrew Borg

Aug 10, 2014
42
Disconnect the bridge,
Measure the resistance between the alternator outputs. Three readings.
Measure the output voltage between the three alternator outputs when running. Three readings.

Measure the resistance or voltage drop of each diode at both polarity. Twelve readings.
If one reading is different to the rest, disconnrct one end and measure it on its own.
Measure voltage drop across the bridge at each polarity. Two readings.
Thanks guys for response here is my circuit but capacitor not charging don't know why is this??!!!

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#### bertus

Moderator
Nov 8, 2019
2,721
Hello,

Can you measure the AC voltage between the phases?

Bertus

#### Andrew Borg

Aug 10, 2014
42
Hello,

Can you measure the AC voltage between the phases?

Bertus
Depends how much generator is spinning but measured it all giving same voltage.

#### bertus

Moderator
Nov 8, 2019
2,721
Hello,

What capacitor do you use?
You have given no information on that.

Bertus

#### Andrew Borg

Aug 10, 2014
42
Hello,

What capacitor do you use?
You have given no information on that.

Bertus
I am trying many but not one is holding charge. Is it maybe frequency problem??
Cannot understand why.

#### bertus

Moderator
Nov 8, 2019
2,721
Hello,

You say you have tried several capacitors.
What where the values of them?
Is there a load accross the capacitor?
Depending on the load, the capacitor will be drained sooner or later.

Bertus

#### duke37

Jan 9, 2011
5,364
Unless youu have a very sophisticated meter, it will discharge the capacitor. To get a significant discharge time you will need a large electrolytic capacitor and a meter with 10M input resistance.

#### Andrew Borg

Aug 10, 2014
42
Hello,

You say you have tried several capacitors.
What where the values of them?
Is there a load accross the capacitor?
Depending on the load, the capacitor will be drained sooner or later.
Bertus
No I tried with no load

Unless youu have a very sophisticated meter, it will discharge the capacitor. To get a significant discharge time you will need a large electrolytic capacitor and a meter with 10M input resistance.
I used it on other capacitor without problem.

#### crutschow

May 7, 2021
517
I am trying many but not one is holding charge
What do you mean "not one is holding charge"?

#### Martaine2005

May 12, 2015
4,351
The OP never returned to this thread.
Two years too late!

Martin

Moderator
Nov 17, 2011
12,720

#### Minder

Apr 24, 2015
3,318
The OP never returned to this thread.
Two years too late!

Martin
He'd depleted all his 'spent' up energy!

#### davenn

Moderator
Sep 5, 2009
14,077
deletion and tidy up

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